C++ :

#include<bits/stdc++.h>
using namespace std;
int n,a,b,c,d,e;
int main()
{
	cin>>n;
	e=n%10;n/=10;
	d=n%10;n/=10;
	c=n%10;n/=10;
	b=n%10;n/=10;
	a=n;
	if(a<b&&b<c&&c>d&&d>e)cout<<"yes";
	else cout<<"no";
	return 0;
}